Explosive jumping: extreme morphological and physiological specializations of Australian rocket frogs (Litoria nasuta).

Abstract Anuran jumping is an ideal system for examining the relationships between key morphological, physiological, and kinematic parameters. We used the Australian rocket frog (Litoria nasuta) as a model species to investigate extreme specialization of the vertebrate locomotor system for jumping. We measured the ground reaction forces applied during maximal jumps using a custom-designed force platform, which allowed us to calculate instantaneous measures of acceleration, velocity, power output, and total jump distance. We quantified the mechanical properties of the plantaris longus muscle using the work loop technique. We found that L. nasuta achieved the second-longest relative jumping distance for any anuran (55.2 body lengths for one individual) and the highest published anuran values for isolated net mean muscle power output measured using work loops (93.5 W kg(-1) muscle mass), hindlimb length to snout-vent length ratio (2.02), and relative hindlimb muscle mass (33% of body mass). Litoria nasuta also had a higher ratio of tibia length to snout-vent length than 19 related species. We found that the mean power output expended during the takeoff phase of jumping in the individual that jumped the farthest was about three times greater than our estimate of available muscle power output.